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(No Model.)

T. L. 8v T. J. STURTEVANT.

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Untrrnn Sterns Parenti trice@ THOMAS L. STURTEVANT AND THOMAS J.STUR'IEVANT, OF FRAMINGHAM, MASSACHUSETTS.

BOILER.l

SPECIFICATION forming part of Letters Patent No. 488,229, dated December20, 1892.

Application led September 7, 1892. Serial No. 445,290. (No model.)

To all whom t may concern:

Be it known that We, THOMAS L. STURTE- vANT and THOMAS J. STURTEVANT,citizens of the United States, residing at Framingham,

in the county 0f Middlesex and State of Massachusetts, have inventedcertain new and useful Improvements in Boilers; and We do hereby declarethe following to be a full, clear, and exact description of theinvention, such as 1o will enable others skilled in the art to which itappertains to make and use the same, reference being had to theaccompanying drawings, and to gures of reference marked thereon, whichform a part of this specification.

This invention relates to that class of boilers termed verticalsubmerged tubular, or such class as have water protected tubes, and itmay be considered as pertaining to an improvem ent upon that shown anddescribed 2o under Serial No. 432,264, tiled May 9, 1892,

jointly in our names.

The essential characteristics consist in a common steam space togetherwith a central steam dome, independent water levels and a steamdischarge in common. In connection therewith We provide an annulartubular portion with an extended steam space formed by a closed drum,also an inner steam generating receptacle, which extends from the crown-3o plate to or not quite to the top of the drum, when thereis an openingto connect the steam spaces, in order to allow the steam therefrom tocommingle with that generated in the tubular portion. Other details ofconstruction 3 5 will be hereinafter described.

The drawings show in Figure l a vertical central sectional elevation ofa boiler embodying our invention. Fig. 2 is an elevation. Fig. 3 is ahorizontal cross-section.

The principal component parts consist of an outer shell 2, a combustionchamber 3, gratebars 4, a central generating receptacle 5, a stack 6,and fines 7. A crown-plate 8 and a tube-plate 9 together with the saidflues form the main steam generating portion, the lues being arranged inan annular group having the central part without them. Attached to thetube plate by a steam joint rises a cylindrical drum 10, which serves asan extended 5o steam space; said drum is above that portion unoccupiedby flues, and receives the steam through the openings 12 in thetube-plate 9.

Centrally of this boiler is placed the generating receptacle 5 beforementioned, and this is united to the crown-plate by a steam joint beingopen at the top in order thata common steam space may be provided for.Moreover said receptacle is made tapering in order to afford space inthe top plate to allow for passage of steam thereabout into the drum.In- 6o dependent supply and discharge pipes 13, 14 enter the tubularportion of the boiler, While similar pipes 15, 16 serve to supply Waterto the central receptacle 5.

In Fig. 1, we have shown the boiler as adapted for separate water-levelswith a common steam space, but each may be. operated, separately, inwhich event the tapered inner receptacle 5 may be united at the top tothe drum and valves 1S, 19 (indicated in broken 7o lines) employed topermit communication or not as may be desired. That is, if the valve 18is open the water levels are independent with a common steam Space; butwith the Valve 19 open, a common Water level, and 75 steam space incommon is obtained. In connection with these valves separate water gages20, 21 are attached when two water-levels are to be carried. In thistype of boiler one of the essential points is the arrangement of the 8oparts, whereby separate water-levels are carried with a steam space incommon. Hence impure water can be used in the inner receptacle of simpleconstruction, which can be readilycleansed, of impurities, while thetubu- -lar and more complicated portion Will contain pure water, and thesteam made will commingle when wanted.

What we claim is:

1. In a boiler the combination with a steam 9o generator, and a drum forextended steam space of a second steam and Water receptacle inclosed bysaid steam generatorand adapted to extend within the drum, a commonsteam delivery together with separate supply and discharge pipes adaptedto maintain independent Water levels, substantially as eX- plained. A

2. In a compound boiler, the combination with a steam and Waterreceptacle having a roo series of vertical lines which interconnect thefire-box and stack, of a second receptacle inclosed by the first, and asteam drum common to both receptacles and which is surmounted on theiirst-named receptacle and covers the part thereof not furnished withtiues, substantially as set forth.

3. In a compound boiler, an exterior steam generating section, havingsupply and discharge pipes, a series of flues, a stack which co-operateswith said iues, and a drum for extended steam, space Within said stack,combined with a cylindrical, steam generating section inclosed Withinthe iirst,independent supply and discharge pipes, therefor, a tirebox incommon to both sections, and a common steam delivery, substantially asset forth.

4. A compound boiler, composed of an exterior steam generating section,having a series of flues therethrough, an apertured top portion, and adrum Which surmounts said apertured portion, combined with a coniformsection secured to the bottom of the exterior section and adapted toextend Within the drum, and communicate therewith, a steam deliverycommon to both sections, and separate supply and discharge pipes, aslikewise separate water-gages for independent Water levels,substantially as described.

5. In a boiler the combination with an exterior Water and steamreceptacle, its independent feed and discharge pipes, and drum forextended steam space, of an interior coneshaped partition attached tothe base of said receptacle, and extending into the drum with which itcommunicates, feed and discharge pipes to maintain a separatewater-level Within said partition, and a tire-box, and steam deliverypipe in common to both steam-generating portions, substantially asexplained.

In testimony whereof We afx our signatures in presence of two Witnesses.

THOS. L. STURTEVANT. THOMAS J. STURTEVANT.

Witnesses:

I-I. E. LODGE, FRANCIS C. STANWooD.

